As much as the refrigerator, lighting, TVs, computers, and stereos combined. In fact, 10% of all U.S. energy is controlled by thermostats. That’s the equivalent of 1.7 billion barrels of oil per year.

But in most homes the thermostat is an unassuming beige box. It doesn’t matter if it’s a manual or complicated programmable thermostat, we do with it what we’ve always done: get up, walk over to it, and change the temperature. Every few hours. Every day. 1,500 times a year.

We still try to save energy, of course. We turn down the thermostat when we can, we don’t set it too high or low. But we’re human. We forget. Until we see our energy bills.